Bhuiyan Mohammad Iqbal H, Song Shanshan, Yuan Hui, Begum Gulnaz, Kofler Julia, Kahle Kristopher T, Yang Sung-Sen, Lin Shih-Hua, Alper Seth L, Subramanya Arohan R, Sun Dandan
1 Department of Neurology, University of Pittsburgh, Pittsburgh, USA.
2 Department of Pathology, University of Pittsburgh, Pittsburgh, USA.
J Cereb Blood Flow Metab. 2017 Aug;37(8):2780-2794. doi: 10.1177/0271678X16675368. Epub 2016 Jan 1.
With-no-lysine kinase (WNK) and Na-K-2Cl cotransporter 1 (NKCC1) are involved in the pathogenesis of hypertension. In this study, we investigated the WNK-NKCC1 signaling pathway in spontaneously hypertensive rats (SHR) and their associated susceptibility to stroke injury. Basal NKCC1 protein levels were higher in SHR than in normotensive Wistar Kyoto (WKY) rat brains. After inducing ischemic stroke, adult male WKY and SHR received either saline or NKCC1 inhibitor bumetanide (10 mg/kg/day, i.p.) starting at 3-h post-reperfusion. NKCC1 inhibition blunted the extent of ischemic infarction in SHR and improved their neurobehavioral functions. Interestingly, ischemia led to increased NKCC1 phosphorylation in SHR but not in WKY rats. Pronounced elevation of WNK1, WNK2 and WNK4 protein and downregulation of WNK3 were detected in ischemic SHR, but not in ischemic WKY rats. Upregulation of WNK-NKCC1 complex in ischemic SHR brain was associated with increased Ca-binding protein 39 (Cab39), without increases in Ste20-related proline alanine-rich kinase or oxidative stress-responsive kinase-1. Moreover, subacute middle cerebral artery stroke human brain autopsy exhibited increased expression of NKCC1 protein. We conclude that augmented WNK-Cab39-NKCC1 signaling in SHR is associated with an increased susceptibility to ischemic brain damage and may serve as a novel target for anti-hypertensive and anti-ischemic stroke therapy.
无赖氨酸激酶（WNK）和钠-钾-2氯共转运体1（NKCC1）参与高血压的发病机制。在本研究中，我们调查了自发性高血压大鼠（SHR）中的WNK-NKCC1信号通路及其与中风损伤易感性的关系。SHR的基础NKCC1蛋白水平高于正常血压的Wistar Kyoto（WKY）大鼠脑内的水平。诱导缺血性中风后，成年雄性WKY和SHR在再灌注后3小时开始接受生理盐水或NKCC1抑制剂布美他尼（10mg/kg/天，腹腔注射）。抑制NKCC1可减轻SHR的缺血梗死范围并改善其神经行为功能。有趣的是，缺血导致SHR中NKCC1磷酸化增加，而WKY大鼠中未出现这种情况。在缺血的SHR中检测到WNK1、WNK2和WNK4蛋白明显升高，WNK3下调，但缺血的WKY大鼠中未出现此情况。缺血性SHR脑中WNK-NKCC1复合物的上调与钙结合蛋白39（Cab39）增加有关，而Ste20相关富含脯氨酸丙氨酸的激酶或氧化应激反应激酶-1未增加。此外，亚急性大脑中动脉中风人脑尸检显示NKCC1蛋白表达增加。我们得出结论，SHR中增强的WNK-Cab39-NKCC1信号与缺血性脑损伤易感性增加有关，可能作为抗高血压和抗缺血性中风治疗的新靶点。
